Berlin 2008 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 14: Electric, electromechanical and optical properties II

DF 14.3: Vortrag

Donnerstag, 28. Februar 2008, 14:40–15:00, EB 407

Light-induced absorption in electrooptic PLZT ceramics — •Torsten Granzow¹, Silke Schaab¹, Dominik Schaniel², and Theo Woike² — ¹FB Material- und Geowissenschaften, TU Darmstadt, Germany — ²Institut für Mineralogie, Universität zu Köln, Germany

Transparent polycrystalline materials such as lanthanum-modified lead-zirconate-titanate ceramics (PLZT) have electrical and electrooptical properties that can rival those of single crystals such as lithium niobate (LNB). At the same time, they offer all the advantages of ceramics, e.g. quick and cheap production in nearly arbitrary shape and size. However, there has been hardly any investigation of light-induced changes of the optical properties of PLZT such as its photorefractive behavior or light-induced changes of the optical absorption.

In this talk, we present measurements of the light-induced absorption in PLZT containing 8% La, 65% Zr and 35% Ti (PLZT 8/65/35). The samples are illuminated by a pulse from a Nd:YAG-laser, the resulting absorption change is detected by measuring the intensity of a probe laser behind the sample. A strong light induced absorption is detected in a broad spectral range. Its temporal development strongly depends on the probing wavelength: at high wavelengths there is a continuous decrease, lower wavelengths show an increase of the absorption for several microseconds before this absorption also finally subsides. This effect is attributed to the presence of two different electronic centers in the band gap. The results are discussed in comparison to LNB single crystals and with respect to possible photorefractive applications.